The present invention relates to a shear-thickening solution containing hydroxypropyl cellulose. More particularly, the invention concerns a composition which will increase in viscosity upon shear under certain conditions comprising hydroxypropyl cellulose and sodium dodecyl sulfate or certain alkylbenzene sulfonates.
Most hydrocarbons and aqueous solutions exhibit Newtonian behavior. Most polymer solutions exhibit shear-thinning behavior, wherein the application of shear to the solution decreases solution viscosity. The principle reason for this behavior is due to the large volume which a single polymeric chain can occupy within the solvent. An increase in the size of the chain produces an increase in solution viscosity. Shearing decreases the size and length of the polymer chains in solution which give the added viscosity to the solution.
Some polymer solutions, however, are known to exhibit shear-thickening behavior if they are prepared in certain concentration ranges. In these cases, viscosity increases upon the application of shear.
Several uses have been developed for solutions having the unusual property of the shear-thickening. Oil production uses abound, including well control fluids, viscosifiers for oil recovery, workover fluids, hydraulic fracturing fluids, mobility control fluids and permeability reduction fluids. Non-petroleum production uses include anti-misting additives for jet fuel (U. S. Statutory Invention Registration H363 and West German No. 3,439,796), grease additives (U.S. Pat. No. 4,132,658), pastes for printing (Poland No. 94,623) and consumer products such as toothpaste (U.S. Pat. No. 4,313,765 and Japan No. 58,062,108 A2).
U.S. Pat. Nos. 4,096,326; 4,313,765 and 4,524,003 disclose shear-thickening compositions useful as general viscosifying agents. U.S. Pat. No. 4,096,326 discloses that water soluble dihydroxypropyl ethers of cellulose form shear-thickening compositions. U.S. Pat. No. 4,313,765 teaches a shear-thickening blend of cellulase-free xanthan gum with a number of cellulose compounds, including carboxymethyl cellulose, hydroxyethyl cellulose and hydroxypropylmethyl cellulose. U.S. Pat. No. 4,524,003 discloses a shear-thickening mixture of at least one member selected from the group consisting of (1) sulfonated guar and a compound comprising at least one member selected from the group consisting of xanthan gum, guar, hydroxpropyl guar or derivatives, hydroxyethyl cellulose or derivatives, and (2) cationic guar and a compound comprising at least one member selected from the group of hydroxypropyl guar or derivatives and hydroxyethyl cellulose or derivatives.
Well control and workover fluids provide a fertile field for the use of shear-thickening compounds. U.S. Pat. No. 3,523,581 claims the use of a mixture of a shear-thickening compound and a sacrificial agent in an enhanced oil recovery process, wherein the shear-thickening/sacrificial agent solution is injected into a reservoir followed by the injection of a driving fluid.
Shear-thickening well control fluids containing clay are disclosed in U.S. Pat. Nos. 4,542,791; 4,663,366 and 4,683,953. U.S. Pat. No. 4,542,791 teaches plugging a porous formation in a wellbore with a water-in-oil emulsion. The continuous phase has granular bentonite and a polyamine surfactant. The aqueous phase contains a solution of a polyacrylamide and a polycarboxylate acid. U.S. Pat. No. 4,683,953 teaches clay with a polyacrylic acid and polyacrylamide. U.S. Pat. No. 4,663,366 employs polycarboxylic acid.
Two other variations of shear-thickening fluids for petroleum production are disclosed in U.S. Pat. Nos. 4,212,747 and 4,289,203. The shear-thickening fluids are said to be useful for mobility control, water diversion, hydraulic fracturing and workover fluids. Both patents disclose the reaction product of a high molecular weight polyalkylene oxide and a synthetic resin produced from aldehydes and phenols in an alkaline environment. U.S. Pat. No. 4,244,826 discloses gelled acidic compositions for acid treating by mixing cellulose ethers or polyacrylamides with an acid and gelling the composition by adding an aldehyde and a phenolic.
Hydroxypropyl cellulose has been evaluated for different uses in the oil field. It has been screened for polymer flooding applications, but has not been used extensively because of its generally higher cost. See Szabo, M. T., "An Evaluation of Water-Soluble Polymers for Secondary Oil Recovery-Part One," Journal of Petroleum Technology, 1979, page 553-560.
Gel systems have been formulated using hydroxypropyl cellulose and a suitable cross-linking agent such as titanium, zirconium or antimony. U.S. Pat. Nos. 4,378,049; 4,553,601 and 4,679,645 all disclose gel systems with cross-linking agents.
U.S. Pat. No. 4,627,494 describes a method of using hydroxypropyl cellulose as a sacrificial agent for surfactant floods. Water-soluble suspensions of hydroxypropyl cellulose and other polymers are disclosed in European Patent Application No. 81301140.0.
British Petroleum has published a report that describes their efforts to develop a "sea water-soluble precipitable polymer" for use in the North Sea. A large slug of hydroxypropyl cellulose was required to achieve a small permeability reduction. See Graham, D. E. et al., "Treatment Fluids to Improve Sea Water Injection," New Technologies for the Exploration and Exploitation of Oil and Gas Resources, Graham and Trotman, Volume Two, 1984, page 860-872.
U.S. Pat. No. 4,169,818 and 4,172,055 disclose the use of hydroxypropyl cellulose with polymaleic and hydroxy derivatives to form a fluid with increased viscosity. The references disclose use as a hydraulic fluid in well drilling operations.
An invention method for decreasing formation permeability around a wellbore is disclosed in U.S. patent application Ser. No. 579,139, filed Sept. 7, 1990. This invention employs hydroxypropyl cellulose and an alkali metal dodecy sulfate in the ratio of about 3:1 to about 1:1.5 of cellulose to sulfate. A brine having a salinity greater than about 10,000 ppm TDS is required to mix and react with the aqueous solution to form a gel. The mixing of the hydroxypropyl cellulose, alkali metal dedecyl sulfate and brine forms a high viscosity gel useful for decreasing formation permeability. Gels formed by this invention method are not shear-thickening.